PostgreSQL Connector

The PostgreSQL connector allows querying and creating tables in an external PostgreSQL database. This can be used to join data between different systems like PostgreSQL and Hive, or between two different PostgreSQL instances.

Configuration

To configure the PostgreSQL connector, create a catalog properties file in etc/catalog named, for example, postgresql.properties, to mount the PostgreSQL connector as the postgresql catalog. Create the file with the following contents, replacing the connection properties as appropriate for your setup:

connector.name=postgresql
connection-url=jdbc:postgresql://example.net:5432/database
connection-user=root
connection-password=secret

Multiple PostgreSQL Databases or Servers

The PostgreSQL connector can only access a single database within a PostgreSQL server. Thus, if you have multiple PostgreSQL databases, or want to connect to multiple PostgreSQL servers, you must configure multiple instances of the PostgreSQL connector.

To add another catalog, simply add another properties file to etc/catalog with a different name (making sure it ends in .properties). For example, if you name the property file sales.properties, openLooKeng will create a catalog named sales using the configured connector.

Querying PostgreSQL

The PostgreSQL connector provides a schema for every PostgreSQL schema. You can see the available PostgreSQL schemas by running SHOW SCHEMAS:

SHOW SCHEMAS FROM postgresql;

If you have a PostgreSQL schema named web, you can view the tables in this schema by running SHOW TABLES:

SHOW TABLES FROM postgresql.web;

You can see a list of the columns in the clicks table in the web database using either of the following:

DESCRIBE postgresql.web.clicks;
SHOW COLUMNS FROM postgresql.web.clicks;

Finally, you can access the clicks table in the web schema:

SELECT * FROM postgresql.web.clicks;

If you used a different name for your catalog properties file, use that catalog name instead of postgresql in the above examples.

PostgreSQL Update/Delete Support

Create PostgreSQL Table

Example:

CREATE TABLE postgresql_table (
    id int,
    name varchar(255));

INSERT on PostgreSQL tables

Example:

INSERT INTO postgresql_table
  VALUES
     (1, 'Jack'),
     (2, 'Bob');

UPDATE on PostgreSQL tables

Example:

UPDATE postgresql_table
  SET name='Tim'
  WHERE id=1;

Above example updates the column name's value to Tim of rows with column id having value 1.

SELECT result before UPDATE:

lk:default> SELECT * FROM postgresql_table;
id | name
----+------
  1 | Jack
  2 | Bob
(2 rows)

SELECT result after UPDATE

lk:default> SELECT * FROM postgresql_table;
id | name
----+------
2 | Bob
1 | Tim
(2 rows)

DELETE on PostgreSQL tables

Example:

DELETE FROM postgresql_table
  WHERE id=2;

Above example delete the rows with column id having value 2.

SELECT result before DELETE:

lk:default> SELECT * FROM postgresql_table;
 id | name
----+------
  2 | Bob
  1 | Tim
(2 rows)

SELECT result after DELETE:

lk:default> SELECT * FROM postgresql_table;
 id | name
----+------
  1 | Tim
(1 row)

PostgreSQL Connector Limitations

The following SQL statements are not yet supported:

GRANT, REVOKE, SHOW GRANTS, SHOW ROLES, SHOW ROLE GRANTS

有奖捉虫

“有虫”文档片段

0/500

存在的问题

文档存在风险与错误

● 拼写,格式,无效链接等错误;

● 技术原理、功能、规格等描述和软件不一致,存在错误;

● 原理图、架构图等存在错误;

● 版本号不匹配:文档版本或内容描述和实际软件不一致;

● 对重要数据或系统存在风险的操作,缺少安全提示;

● 排版不美观,影响阅读;

内容描述不清晰

● 描述存在歧义;

● 图形、表格、文字等晦涩难懂;

● 逻辑不清晰,该分类、分项、分步骤的没有给出;

内容获取有困难

● 很难通过搜索引擎,openLooKeng官网,相关博客找到所需内容;

示例代码有错误

● 命令、命令参数等错误;

● 命令无法执行或无法完成对应功能;

内容有缺失

● 关键步骤错误或缺失,无法指导用户完成任务,比如安装、配置、部署等;

● 逻辑不清晰,该分类、分项、分步骤的没有给出

● 图形、表格、文字等晦涩难懂

● 缺少必要的前提条件、注意事项等;

● 描述存在歧义

0/500

您对文档的总体满意度

非常不满意
非常满意

请问是什么原因让您参与到这个问题中

您的邮箱

创Issue赢奖品
根据您的反馈,会自动生成issue模板。您只需点击按钮,创建issue即可。
有奖捉虫